鄂尔多斯盆地延长油气区石盒子组盒8段储层成岩作用研究

RESERVOIR DIAGENESIS OF SHIHEZI 8 MEMBER, YANCHANG OIL AND GAS REGION IN ORDOS BASIN

根据薄片、铸体薄片、扫描电镜、X-衍射及化验分析等资料,对延长油气区盒8段储层的岩石学特征、成岩作用类型和阶段划分及其对孔隙的影响进行了研究。研究表明,该区盒8段储集岩以岩屑石英砂岩为主,成分成熟度较高,结构成熟度较低。成岩作用类型主要包括:压实作用、胶结作用和溶蚀作用。目前基本处于晚成岩阶段的B期,部分进入晚成岩C期。早成岩A期至晚成岩B期的压实作用、晚成岩A期的交代蚀变作用是使物性变差的两个重要因素;晚成岩B-C期的充填胶结作用是储层质量变差的又一原因,绿泥石环边胶结和溶蚀作用则是储层物性变好的重要成岩控制因素。

In this paper, the petrological characteristics, diagnesis type and diagenetic-stage classification, and their impact on pore are studied for Shihezi 8 Member of Yanchang oil and gas region based on some data of thin section, casting thin section, SEM and X-refraction. Results show that: (1) this reservoir is mainly composed of lithic quartz sandstone with a higher composition maturity and a lower texture maturity; (2) diagenesis mainly include compaction, cementation and dissolution; (3) it is basically in late diagenetic stage B, partly in late diagenetic stage C; (4) the compaction from early diagenetic stage A to late diagenetic stage B and the metaomatic alteration in late diagenetic stage A are the two important factors which can make physical property poorer; (5) the packing and cementation are other factors; and (6) the cementation and dissolution around chlorite rim are the other factors which can make physical property better.